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What is Bluetooth?

If you have been around the mobile electronics industry for any amount of time, you will know that certain terms are often used incorrectly. One term that has been over-abused lately is Bluetooth. Product manufacturers, retailers and consumers have developed an expectation of what Bluetooth is, and what it does. Sadly, those expectations can lead to confusion and undesirable results. This article explains what Bluetooth is, and how it is used.

What is Bluetooth?

Back in the dark ages, we had to connect electronic devices with wires. We also created wheels from boulders using animal bones as tools. RS-232 was a popular type of communication protocol for devices like modems, printers, scanners and cameras. Two wires would carry data between these devices and your computer. In 1994, Ericsson – a telecommunications and network equipment manufacturer in Stockholm, Sweden – introduced a wireless alternative to RS-232 called Bluetooth.

Bluetooth is a low-power, high-speed wireless communication protocol. Bluetooth operates using short-wave UHF radio waves in the frequency band of 2.4 to 2.485 GHz. Within this range of frequencies are 79 dedicated Bluetooth channels. Bluetooth uses Frequency Hopping Spread Spectrum to reduce errors and allow multiple devices to operate within the same frequency spectrum.

Bluetooth is used for short-range data communication between devices like computer and keyboards, video game controllers and consoles, and cellular phones and wireless devices. There are applications for medical applications such as monitoring heart rate, blood pressure and glucose levels. That said, many industrial applications exist between sensors in production systems and control computers.

Bluetooth Profiles

The misconception many people in the mobile electronics industry have is that Bluetooth exists to let cellular phones make calls and stream music to our radios. Bluetooth is far more involved and flexible than that.

Any talk of Bluetooth functionality is a perfect segue to introduce us to profiles. A Bluetooth profile is a set of instructions and commands that operate over a Bluetooth connection. Profiles simplify the communication between devices. In our industry, we are used to four common profiles:

PBAP – Phonebook Access Profile

HFP – Hands-free Profile

A2DP – Advanced Audio Distribution Profile

AVRCP – Audio Video Remote Control Profile

These profiles are used in varying combinations to allow you to connect your phone to your car radio so you can make phone calls and stream music. A few companies that have wanted to provide an Internet connection to their radio have used DUN to accomplish this task.

PBAP Profile

The Phone Book Access Profile allows your source unit to receive phonebook entry information, as well as manage it. Phonebook entries are transmitted and managed by the radio in vCard 2.1 or vCard .0 formats. Missed, received and dialed numbers are listed as well.

HFP Profile

The Hands-free Profile carries monaural audio between the phone and a secondary device. The profile also supports commands to answer or reject incoming calls; place a call; use memory data to place a call, terminate a call or manage phone volume level; and send phone status information, including battery, roaming status and signal strength . These functions are included in version 1.5 of the Hands-free Profile. Future versions, such as 1.7, will include support for wideband speech and the use of external audio compression and decompression codecs.

A2DP Profile

The Advanced Audio Distribution Profile operates within another profile called the Generic Audio/Video Distribution Profile (GAVDP). A2DP is responsible for allowing us to stream audio from a device such as a smartphone to a radio or powered speaker. The basic profile allows for stereo audio to be transmitted at a sampling frequency of 44.1 kHz at up to 328 kb/s. The use of a third-part codec such as aptX from Qualcomm or LDAC from Sony may further improve on bandwidth.

AVRCP Profile

Functioning alongside the GAVDP profile is the Audio Video Remote Control Profile. AVRCP is responsible for the display of song title, artist and album information, and control over playback device functions. If you can imagine a button on a DVD remote control, the AVRCP is likely to support it. Most car audio source units include functions like play, pause, fast-forward and rewind. The most recent versions of AVRCP include support for folder navigation and searching.

What Bluetooth Doesn’t Do

Although the Bluetooth Special Interest Group (SIG) works to manage the different Bluetooth communication and profile standards, there are variations in functionality between profile versions and, more importantly, between smartphone vendors. This latter fact can be a significant issue for buyers of car audio source units. The expectation that it “should work,” while not unreasonable, is not always possible. To expect a seven- or eight-year-old radio to work flawlessly with a brand-new iPhone 7 or Samsung Galaxy S8 isn’t reasonable. The hardware in the older units cannot be upgraded.

How to Buy Bluetooth

If you are shopping for a new source unit, take any smartphone you want to use with it to the retailer. Ask to pair your phone with the demo unit on display. Check that your entire list of phone contacts transfers as expected. Make sure you can use voice control functions if they apply to your phone. See that you can make calls easily. Finally, check that your phone reconnects reliably to the source unit by cycling power on the source a few times.

If you purchase a new radio and have it installed, only to find out it is not compatible with your smartphone, there is often nothing that can be done quickly. Some manufacturers do release updates for Bluetooth functionality, but these updates are not going to turn a Bluetooth 3.0 system into a 4.0, or add AVRCP 1.4 to a system that shipped with AVRCP 1.2. Do your research before you buy!

If you are looking for a hands-free solution to make phone calls or stream music to your audio system, drop in at your local mobile electronics specialist retailer. Bring your phone, pair the Bluetooth connection and experiment with the options.

This article is written and produced by the team at www.BestCarAudio.com. Reproduction or use of any kind is prohibited without the express written permission of 1sixty8 media.

Product Spotlight: Sony XAV-AX8500 Multimedia Receiver

Floating-face car radios are popular because of their flexible installation options and relatively massive displays. The Sony team has been hard at work updating their products, and the new 10.1-inch XAV-AX8500 digital multimedia receiver is their latest offering in this hot market segment. Let’s see what’s been added to the platform to keep it at the forefront of the category.

High-Definition 10.1-inch Floating Face Display

The first thing you’ll see in the XAV-AX8500 is its classy 10.1-inch HD display. The screen has a resolution of 1280 by 720 pixels. The touch panel has an anti-glare coating and features a capacitive-touch interface. Compared with a resistive-touch interface, the capacitive design obscures the display less, making the information on the display easier to see. The gapless design around the screen lets it blend into the display chassis. Sony leads the industry in clean and classy styling. While it might not be flashy or attention-grabbing on a display board, it looks as though it belongs in your car or truck rather than at the helm of an intergalactic spacecraft.

Sony XAV-AX8500 — The 10.1-inch High-Definition capacitive-touch screen features an anti-glare design so information is easily visible.

One of the most interesting features of this model is the multiple adjustments that can be made during and after installation in the dashboard. During installation, your technician can set, in relation to the chassis, the vertical height, the horizontal left to right position, and the depth between the screen and the chassis mount, and can tilt the screen forward and back to accommodate most dashboard slopes.

After installation, during normal use, you can adjust the screen position, with no tools or disassembly. You can swivel the screen up to 15 degrees left or right to fine-tune the viewing angle in relation to your seating position or for a passenger to view it easier, and tilt the screen forward or backward up to 15 degrees as well to mitigate any direct sunlight shining on it or to improve visibility.

The screen interface is similar to what we experienced in the XAV-9500ES Test Drive Review, with five icons across the bottom. You can pull up a complete list of additional source and setting options and swap any of them into these five primary locations. You can also upload custom wallpapers to the radio to add some personalization or choose from several preset color schemes.

This radio includes six physical buttons along the bottom of the display, making it intuitive to adjust the volume, change sources or activate voice recognition for CarPlay and Android Auto. Hard buttons, as they are called, are crucial to using the radio while keeping your eyes on the road.

Source Features

Nowadays, most people stream music from online services like Pandora, iHeartRadio or Spotify. The XAV-AX8500 includes Bluetooth streaming with radio-based control over track selection. As a Sony product, this unit also includes the high-quality LDAC codec to improve performance with modern Android-based smartphones.

Apple CarPlay and Android Auto smartphone integration is included, and wireless connectivity means your phone connects just after the radio finishes booting. Speaking of which, the Quick Wake-up design ensures that you have a rearview camera image and music playing seconds after you start the vehicle.

Of course, you can connect a USB memory stick to play MP3, WMA, WAV, ACC, FLAC, ALAC, DSF and even DSDIFF audio files. You can view AVI, MKV, MPEG-4, WMV and ASF video files to pass the time when parked. Speaking of video, there’s a micro-HDMI input beside the USB-C port on the rear panel that will work with a smartphone, laptop or even a media player. It supports video file resolutions up to 720p.

The integrated AM/FM receiver includes RBDS to show station information so you know what track is playing. Your installer can add a SiriusXM satellite radio receiver at installation time for uninterrupted entertainment from coast to coast.

Vehicle Integration and Safety Features

A significant highlight of the Sony XAV-AX8500 is that it supports the iDatalink Maestro RR and RR2 vehicle integration modules. If a Maestro RR is available for your vehicle, the radio can communicate with the vehicle computers to display information like speed, engine rpm, etc. In some applications, Maestro RR interfacing includes climate control and vehicle setting menus. Check with the retailer you’re working with for additional details.

Regarding audio features, the radio has a four-channel amplifier rated for 20 watts RMS per channel into a 4-ohm load at less than 1% THD+N. The front, rear and subwoofer preamp outputs can produce 5 volts of signal, so the gains on amplifiers can be set nice and low.

On the topic of audio features, the radio has a 14-band graphic equalizer and adjustable high-pass crossovers for the front and rear powered and preamp channels. A subwoofer crossover with polarity and level control for the preamp signal is also included. Signal delay settings are available for the front, rear, and mono subwoofer output to fine-tune the soundstage and imaging in your vehicle. Be sure to ask your installer about configuring these features during installation.

The Sony has a dedicated backup camera input and two additional video camera connections that can be used with a forward-facing camera or blind spot monitoring solutions. These camera inputs can be integrated with the Maestro module for automatic activation in a supported vehicle, or by the hardwire triggers included in the video harness. The radio includes an external Bluetooth microphone to optimize outgoing voice clarity.

Upgrade Your Vehicle with the Sony XAV-AX8500 Digital Multimedia Receiver Today!

If you’re shopping for a high-performance radio for your car, truck or SUV, visit an authorized Sony car audio retailer and ask about the new XAV-AX8500. Be sure to bring your smartphone to experience the intuitive interface and the fantastic responsiveness in person. For more information about this radio or any of Sony’s car audio products, visit their website or Facebook page.

This article is written and produced by the team at www.BestCarAudio.com. Reproduction or use of any kind is prohibited without the express written permission of 1sixty8 media.

When it Comes to Subwoofer Specifications, Some Numbers Don’t Matter

If you are a mobile electronics enthusiast like we are, then it’s quite possible that you enjoy reading product specifications. You can learn a lot about the design and application of a product from the specs. Amplifier power ratings are probably the most popular specs, but there are a lot more. One product specification that tends to confuse people more than help them is speaker efficiency. This article explains what the numbers mean and how you should analyze the appropriateness of subwoofer specifications, one subwoofer to another.

Speaker Efficiency

In a nutshell, the efficiency specification attempts to quantify how much sound a speaker will produce when provided with a given amount of power. Manufacturers provide the specification in two common methods. The most common are decibels of output when fed with 1 watt of power and measured at 1 meter from the speaker, written as 1 W/1 m. The other specification method involves replacing the 1 watt power measurement with 2.83 volts. For a 4 ohm car audio speaker, 2.83 volts works out to 2 watts of power or 4 watts into a 2 ohm speaker. Make sure to take the impedance of the speaker into consideration with the latter format.

For a subwoofer, we derive this efficiency number with a formula that includes the driver’s resonant frequency, equivalent suspension compliance and driver’s electrical Q. In reality, the resulting number is purely theoretical and applies most directly to output in the frequency range above where most subwoofers play. There is the heart of the matter: The efficiency specification doesn’t describe how loud the subwoofer is at low frequencies. The only way to predict and compare performance is to model the behavior of the driver in simulation software.

Frequency Response Simulation

Let’s compare two 10-inch speakers. For sample A, we will use a very high-quality car audio subwoofer. Since we want to make this example somewhat extreme, we will use a 10-inch pro audio woofer as Sample B in our comparison. We will use BassBox Pro 6 to make the comparisons.

Sample A has a calculated efficiency of 93.21 dB when driven with 2.83 V. Sample B has an efficiency of 95.07 dB. Without modeling the low-frequency behavior of the driver, you’d happily think that Sample B was the louder of the two by 1.86 dB.

We modeled each driver in a sealed enclosure with a volume that provides a total system Q (Qtc) of 0.707. The car audio subwoofer is in 0.694 cubic feet, and Sample B is in 0.378 cubic feet net.

As you can see from the graph, the output of the two woofers varies dramatically. Sample A is louder at 40 Hz by an impressive 4.95 dB. That is contradictory to the efficiency specification, isn’t it? It is, however, not wrong.

Subwoofer Specifications

When an engineer designs a speaker, the first thing to decide is the application. Will this be a high-SPL car audio speaker, or a pro-sound speaker? The differences make a great deal of difference.

Our sample subwoofers also have dramatically different excursion capabilities. Sample A has an Xmax of 17.6 mm and Sample B has an Xmax of only 4 mm. It is worth noting and reminding everyone that cone excursion quadruples for every halving of frequency. If these speakers were given enough power to play 100 dB at 80 Hz with an excursion of 1 mm, then they would need to move 4 mm at 40 Hz. At 20 Hz, they would need to move 16 mm. An excursion requirement of 16 mm is no problem for Sample A, but will likely rip Sample B to shreds.

Comparing the output of two drivers requires that we ensure the driver can handle the excursion requirements necessary to meet our needs.

In the case of our subwoofer simulations, due to excursion limits, Sample B can produce a maximum output of only 94.9 dB at 40 Hz. Sample A can produce 108.3 dB at the same frequency. That is a difference of 13.4 dB. This difference is significant. Sample B simply cannot produce 100 dB of output at 40 Hz in this enclosure. Thus, Sample B not a suitable choice for a subwoofer, which makes sense, since it was designed to be a bass guitar speaker.

Choosing the Right Subwoofer

Unless you own speaker-modeling software and know how to use it, it can be tricky to determine the performance of one subwoofer versus another. Even more difficult is attempting to predict how one sounds when compared to another. Frequency response is just one of the many criteria that differentiate one subwoofer from another. Excursion capabilities, enclosure requirements, distortion characteristics and – of course – cost are all factors to be considered.

Many people think that just because it is harder to hear distortion at low frequencies, the design of a subwoofer matters less than that of a midrange speaker. You would be stunned at how a good subwoofer can bring out details in your music that you may have never heard before.

When it is time to go subwoofer shopping, visit your local mobile electronics specialist retailer. Discuss your needs with them and work with them to find a subwoofer solution that fits your application. You will be happy that you did.

This article is written and produced by the team at www.BestCarAudio.com. Reproduction or use of any kind is prohibited without the express written permission of 1sixty8 media.

Product Spotlight: Sony XS-W124GS and XS-W104GS Car Audio Subwoofers

Although talking about a trunk full of high-performance subwoofers powered by big amplifiers is fun, Sony knows that many people want a more cost-effective bass upgrade for their cars and trucks. On the heels of their entirely new Mobile ES amplifiers, source units, speakers and subwoofers, Sony has launched the latest iteration of the GS series speakers and subwoofers. This Product Spotlight will look at the 12-inch XS-W124GS and 10-inch XS-W104GS car audio subwoofers.

Features of the Sony XS-W124GS Subwoofer

The 12-inch (30-cm) XS-W124GS and 10-inch (25-cm) XS-W104GS subwoofers feature five-spoke, heavy-gauge stamped steel frames. Each spoke has an embossed element to add stiffness and rigidity. The frames also feature integrated vents below the spider mounting ledge. These vents allow heat to escape from the voice coil and motor assembly and prevent pressure from building up in the spider at high excursion levels. This design feature offers direct benefits regarding increased power handling, reduced power compression and improved linearity.

The motor assembly at the base of the chassis features a pair of ferrite magnets for good efficiency. The T-yoke has a cooling vent in the center, serving the same purposes as the vents in the frame. Heat can escape from the motor, and pressure won’t build up under the dust cap. The result is an additional reduction in thermal compression and reduced distortion at high volume levels.

A five-spoke, reinforced steel chassis is a rigid platform for the Sony XS-W124GS 12-inch and XS-W105GS 10-inch subwoofers.

Each subwoofer features a pair of progressive-rate spiders attached to the cone assembly to the basket. These spiders are a feature that Sony has brought from the Mobile ES drivers. The spiders provide the necessary cone control and compliance while keeping everything centered. Sony chose moderately stiff spiders to give the drivers a higher Qts value, which translates to improved output efficiency. Tinsel leads are sewn to the spider so they won’t hit the cone and cause unwanted noises at high output levels.

Sony GS Series Subwoofer Moving Components

Both GS series subwoofers feature a rigid paper cone bonded to the voice coil former. You can see in the cutaway image that the upper spider has a reinforcing collar at the base of the cone that strengthens the joint to the voice coil former and spider to improve reliability. A full-size parabolic dust cap made from injection-molded polypropylene attaches to the surround to form the cone assembly’s face. A rubber surround serves as the upper compliance for the woofer cone. Rubber lasts much longer than foam so these woofers will sound great in your car or truck for many years. A custom-tooled trim ring adorns the outer edge of the subwoofer to give it a tidy appearance.

XS-W124GS Physical Dimensions and Driver Specifications

The XS-W124GS subwoofer has an outside diameter of 13 1/8” (332 cm) and requires a mounting hole with a diameter of 11 1/8” (280 cm). The mounting depth is 5 3/4” (143.4 cm), but your installer will want to leave some room for the vent in the T-yoke. Sony rates the XS-W124GS as capable of handling 300 watts of power using the IEC 60286-5 standard and 420 watts using the ANSI/CTA-2031 standard. Peak power handling is 1,800 watts.

Regarding Thiele/Small parameters, the driver has a resonant frequency of 31.9 ohms, an equivalent compliance value (Vas) of 49.194 liters and a Total Q (Qts) of 0.724. As mentioned, the moderately high Q-value will help increase efficiency and output. Suggested enclosures are 0.91 cubic foot for a sealed design and 1.16 cubic feet tuned to 37 hertz for bass reflex applications. The graph below shows the predicted free-field response of the two enclosures, with the driver receiving 420 watts of power.

XS-W104GS Physical Dimensions and Driver Specifications

The 10-inch XS-W104GS has an outer diameter of 11 inches (279 mm), requires a mounting hole with a diameter of 9 1/4 inches (234 mm) and requires 5 1/8 inches (129.8 mm) of depth. Rated power handling is 300 watts continuous and 350 watts using the ANSI/CTA-2031 standard. Peak power handling is 1,500 watts.

The 10-inch subwoofer has an Fs of 30.9 hertz, an equivalence compliance of 36.47 liters and a Total Q of 0.505. By way of enclosures, Sony suggests an acoustic suspension design with a volume of 0.88 cubic foot or a bass reflex enclosure with a volume of 0.91 cubic foot tuned to 38 hertz. Given the similarity in suggested enclosure volumes, we’d go with the bass reflex design and enjoy the increased efficiency.

Sony backs the new 10- and 12-inch GS series subwoofers with a three-year warranty against manufacturing defects and workmanship issues. This generous warranty doesn’t mean you can hook one to a 1,000-watt amp or clip the daylights out of a 400-watt amp and melt the voice coil, then expect to get a new subwoofer.

Upgrade Your Car Audio System with Sony GS series Subwoofers

If you’re looking for an affordable, high-quality subwoofer from a company that stands behind its products, drop into a local authorized Sony car audio retailer today. Ask about the new GS series subwoofers like the XS-W124GS we looked at here. They can match the driver to an enclosure and suggest an amplifier that will perform great. Adding bass to your car stereo is one of the best upgrades you can make. With the Sony GS subwoofers, great sound doesn’t have to cost a small fortune. You can find an authorized Sony Car Audio retailer near you using their dealer locator tool. Also, follow Sony on Facebook to stay up-to-date with their latest product releases.

This article is written and produced by the team at www.BestCarAudio.com. Reproduction or use of any kind is prohibited without the express written permission of 1sixty8 media.

Product Spotlight: KICKER PTRTP Powered Subwoofer System

If you wanted one word to describe the best upgrade you can make to almost any factory-installed car stereo, that word would be subwoofer. For 50 years, the folks at KICKER in Stillwater, Oklahoma, have known that a subwoofer system is the first, best upgrade. When it’s a priority to maximize audio system performance while balancing cargo space, KICKER’s PTRTP powered down-firing loaded subwoofer enclosures are a great choice. Let’s check them out!

KICKER PTRTP10 10-inch Subwoofer System

KICKER created two solutions in the PTRTP line. The PTRTP10 features a 10-inch subwoofer, a 400-watt amplifier and a 10-inch passive radiator. The enclosure is 13.25 inches deep, 25.625 inches wide, and only 6 inches tall. Whether it’s sitting at the back of your trunk or under the seat of a pickup truck, you’ll still have room to carry all your sports equipment, tools, luggage or weekly groceries.

KICKER PTRTP12 12-inch Subwoofer System

If you want a little more kick (pun intended), the PTRTP12 is a perfect solution. This larger enclosure features a 12-inch subwoofer with a matching 12-inch passive radiator and a 500-watt amplifier. Enclosure dimensions are 14.625 inches deep, 27.5 inches wide and 6.5 inches tall. That’s still small enough that you can easily leave it in place on a road trip or vacation.

Standard Features of KICKER’s Down-Firing Amplified Subwoofer Systems

The KICKER PTRTP enclosures feature CompRT-Series subwoofers. This series of subwoofers delivers full-size subwoofer performance from incredibly compact dimensions. The drivers feature an injection-molded polypropylene cone with eight reinforcing spokes. The cones are attached to ribbed Santoprene rubber surrounds. The ribs help improve linearity and prevent buckling and distortion at high output levels. Power handling is improved, and thermal compression is reduced, by a series of forced-air cooling holes in the bottom plate. These holes let hot air around the bottom of the voice coil and motor escape. Vents in the basket under the spider mounting plateau provide additional cooling and reduce compression issues at high excursion levels. The custom-tooled bumped top plate in the CompRT drivers allows for a stunning 13.35-mm Xmax specification.

The amplifiers built into each enclosure are identical in features and only differ in power production. Both include adjustable RCA preamp and speaker-level inputs via a four-pin Molex-style connector. The preamp input can accept up to 5 volts, and the speaker-level input mode will handle an impressive 40 volts. The amplifier can be activated using the standard 12-volt remote input connection or DC-offset detection. The DC-offset circuitry monitors the speaker-level inputs for the DC voltage common to factory-installed and even aftermarket radios. The bottom line is that KICKER has made this easy to integrate with your factory-installed stereo system. If you ever want to temporarily remove the enclosure, the signal and power connections are on quick-release plugs.

The built-in amplifiers include an adjustable -12 dB/octave low-pass crossover that your installer can set between 50 and 120 Hz. A bass boost control can bump 40 Hz by up to 6 dB. Finally, a polarity control switch will invert the output to improve integration with the rest of the speakers in the vehicle. KICKER has included a full-time infrasonic filter set to 25 Hz with a -12 dB/octave slope. Both solutions include a wired remote bass control to let you fine-tune the system from the driver’s seat.

KICKER PTRTP Passive Radiator Subwoofer Systems

Many older car audio enthusiasts will recognize the passive radiator design used in the KICKER PTRTP enclosures from the first KICKER Box subwoofer enclosure systems created in the ’80s. Passive radiator designs offer similar performance benefits to a vented enclosure. So why use them? Passive radiator enclosures can be much smaller than vented enclosures and deliver equally impressive amounts of deep bass.

So why a down-firing enclosure? The primary benefit is driver protection. You can throw your hockey gear or golf clubs in the cargo area without fear of damaging the speaker cone or surrounds. KICKER has added significant reinforcement to the construction of the enclosure to ensure that you aren’t going to crush it. Cosmetically, the enclosures are classy and subtle, with a durable black carpet finish and rounded corners. You can have the embroidered KICKER logo facing rearward for all to see, or your installer can turn it around for a less conspicuous upgrade.

Upgrade Your Car Audio System with KICKER Today!

If you want a compact, high-performance subwoofer upgrade for your car, truck or SUV, drop by a local authorized KICKER retailer and ask about their 10- and 12-inch PTRTP powered down-firing subwoofer systems. You can find a KICKER retailer using the dealer locator on their website. To learn more about KICKER’s amazing car audio products, check out their YouTube channel, Facebook page or Instagram feed.

This article is written and produced by the team at www.BestCarAudio.com. Reproduction or use of any kind is prohibited without the express written permission of 1sixty8 media.

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What is Bluetooth?

What is Bluetooth?